PT-2026-57124 · Room34 · Ics Calendar

Khanh Nguyen

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Published

2026-07-10

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Updated

2026-07-10

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CVE-2026-9838

CVSS v3.1

6.1

Medium

VectorAV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
The ICS Calendar plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'htmltagtitle' parameter in all versions up to, and including, 12.0.9 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. The vulnerability is reachable via the unauthenticated wp ajax nopriv r34ics ajax AJAX action, which accepts attacker-controlled js args values merged over stored shortcode configuration without nonce verification, allowing the htmltagtitle key to bypass the normal shortcode allowlist check.

Fix

XSS

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Weakness Enumeration

Related Identifiers

CVE-2026-9838

Affected Products

Ics Calendar